Hi all
I'm using this code to attempt to capture video from my laptops
The screen appears but all I get is black screen where the video
playback should be. Has any seen this before and know how to fix it
please.
Regards
Graham
Oform=createobject("tform")
Oform.show(1)
DEFINE CLASS Tform As Form
#DEFINE WM_CAP_START 0x0400
#DEFINE WM_CAP_DRIVER_CONNECT (WM_CAP_START+10)
#DEFINE WM_CAP_DRIVER_DISCONNECT (WM_CAP_START+11)
#DEFINE WM_CAP_DRIVER_GET_CAPS (WM_CAP_START+14)
#DEFINE WM_CAP_SET_PREVIEW (WM_CAP_START+50)
#DEFINE WM_CAP_SET_OVERLAY (WM_CAP_START+51)
#DEFINE WM_CAP_SET_PREVIEWRATE (WM_CAP_START+52)
#DEFINE WM_CAP_GET_STATUS (WM_CAP_START+54)
#DEFINE WM_CAP_GRAB_FRAME (WM_CAP_START+60)
Width=340
Height=310
Autocenter=.T.
Caption="Using Video Capture"
MinButton=.F.
MaxButton=.F.
hWindow=0
hCapture=0
capWidth=0
capHeight=0
capOverlay=0
ADD OBJECT cmdGetFrame As CommandButton WITH
Default=.T.,;
Left=15, Top=264, Height=27, Width=90, Caption="Get
Frame",;
Enabled=.F.
ADD OBJECT cmdPreview As CommandButton WITH
Default=.T.,;
Left=106, Top=264, Height=27, Width=100,
Caption="Preview Video",;
Enabled=.F.
ADD OBJECT cmdClose As CommandButton WITH Cancel=.T.,;
Left=250, Top=264, Height=27, Width=70, Caption="Close"
PROCEDURE Activate
IF THIS.hWindow = 0
DECLARE INTEGER GetFocus IN user32
THIS.hWindow = GetFocus()
THIS.CreateCaptureWindow
THIS.DriverConnect
ENDIF
PROCEDURE Destroy
THIS.ReleaseCaptureWindow
PROCEDURE cmdClose.Click
ThisForm.Release
PROCEDURE cmdGetFrame.Click
ThisForm.GetFrame
PROCEDURE cmdPreview.Click
ThisForm.StartPreview
PROCEDURE GetFrame
THIS.msg(WM_CAP_GRAB_FRAME, 0,0)
#DEFINE WM_CAP_FILE_SAVEDIB (WM_CAP_START + 25)
LOCAL lcFile
lcFile = "" && File name to create
lcFile = "c:\temp\sample.bmp"
THIS.msg(WM_CAP_GRAB_FRAME, 0,0)
THIS.msg(WM_CAP_FILE_SAVEDIB, 0, lcFile,1)
PROCEDURE CreateCaptureWindow
#DEFINE WS_CHILD 0x40000000
#DEFINE WS_VISIBLE 0x10000000
DECLARE INTEGER capCreateCaptureWindow IN avicap32;
STRING lpszWindowName, LONG dwStyle,;
INTEGER x, INTEGER y,;
INTEGER nWidth, INTEGER nHeight,;
INTEGER hParent, INTEGER nID
THIS.hCapture = capCreateCaptureWindow("",;
WS_CHILD+WS_VISIBLE,;
10,8,320,240, THIS.hWindow, 1)
PROCEDURE DriverConnect
THIS.msg(WM_CAP_DRIVER_CONNECT, 0,0)
IF THIS.IsCaptureConnected()
THIS.GetCaptureDimensions
STORE .T. TO THIS.cmdGetFrame.Enabled,;
THIS.cmdPreview.Enabled
THIS.Caption = THIS.Caption + ":
connected, " +;
LTRIM(STR(THIS.capWidth)) + "x" +;
LTRIM(STR(THIS.capHeight))
ELSE
THIS.Caption = THIS.Caption + ": failed
to connect"
ENDIF
PROCEDURE DriverDisconnect
THIS.msg(WM_CAP_DRIVER_DISCONNECT, 0,0)
PROCEDURE ReleaseCaptureWindow
IF THIS.hCapture <> 0
THIS.DriverDisconnect
DECLARE INTEGER DestroyWindow IN user32
INTEGER hWnd
= DestroyWindow(THIS.hCapture)
THIS.hCapture = 0
ENDIF
PROCEDURE msg(msg, wParam, lParam, nMode)
IF THIS.hCapture = 0
RETURN
ENDIF
IF VARTYPE(nMode) <> "N" Or nMode=0
DECLARE INTEGER SendMessage IN user32;
INTEGER hWnd, INTEGER
Msg,;
INTEGER wParam, INTEGER
lParam
= SendMessage(THIS.hCapture, msg,
wParam, lParam)
ELSE
DECLARE INTEGER SendMessage IN user32;
INTEGER hWnd, INTEGER
Msg,;
INTEGER wParam, STRING
@lParam
= SendMessage(THIS.hCapture, msg,
wParam, @lParam)
ENDIF
FUNCTION IsCaptureConnected
* analyzing fCaptureInitialized member of the CAPDRIVERCAPS structure
#DEFINE CAPDRIVERCAPS_SIZE 44
LOCAL cBuffer, nResult
cBuffer = Repli(Chr(0),CAPDRIVERCAPS_SIZE)
THIS.msg(WM_CAP_DRIVER_GET_CAPS, Len(cBuffer), @cBuffer,
1)
THIS.capOverlay = buf2dword(SUBSTR(cBuffer,5,4))
nResult = Asc(SUBSTR(cBuffer, 21,1))
RETURN (nResult<>0)
PROCEDURE GetCaptureDimensions
* reading uiImageWidth and uiImageHeight members
* of the CAPSTATUS structure
#DEFINE CAPSTATUS_SIZE 76
LOCAL cBuffer
cBuffer = Repli(Chr(0), CAPSTATUS_SIZE)
THIS.msg(WM_CAP_GET_STATUS, Len(cBuffer), @cBuffer, 1)
THIS.capWidth = buf2dword(SUBSTR(cBuffer,1,4))
THIS.capHeight = buf2dword(SUBSTR(cBuffer,5,4))
PROCEDURE StartPreview
THIS.msg(WM_CAP_SET_PREVIEWRATE, 30,0)
THIS.msg(WM_CAP_SET_PREVIEW, 1,0)
IF THIS.capOverlay <> 0
THIS.msg(WM_CAP_SET_OVERLAY, 1,0)
ENDIF
PROCEDURE StopPreview
THIS.msg(WM_CAP_SET_PREVIEW, 0,0)
ENDDEFINE
FUNCTION buf2dword(lcBuffer)
RETURN Asc(SUBSTR(lcBuffer, 1,1)) + ;
BitLShift(Asc(SUBSTR(lcBuffer, 2,1)), 8) +;
BitLShift(Asc(SUBSTR(lcBuffer, 3,1)), 16) +;
BitLShift(Asc(SUBSTR(lcBuffer, 4,1)), 24)
--- StripMime Report -- processed MIME parts ---
multipart/alternative
text/plain (text body -- kept)
text/html
---
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